1. Field of the Invention
The present invention is related generally to network communication, and more particularly to configuring and re-configuring a router to accommodate variations in parameters for changing from one network interface device to another for the router's network connection.
2. Related Art
For data-intensive service operations where the operations are in many, widely-distributed locations, such as where data is logged for well drilling or production, it is conventional that the service provider has centralized information handling resources which are physically distant from the remote data acquisition sites but accessible by a wide area network (“WAN”). From time to time at least some of the data logged at one of the remote sites needs to be sent to the information handling resources via the WAN. Also, the remote location sometimes needs to be served by the information handling resources via the WAN.
In an application like this, the WAN may be a private network, but it is convenient for it to at least be compatible with the Internet. That is, being a private network, the network does not handle messages sent from outside the network to recipients who are also outside the network. However, with respect to Internet compatibility, the network does permit communication between hosts on the private network and hosts on the Internet outside the private network. Therefore, to facilitate this compatibility with the outside world, hosts on the private WAN may be assigned IP addresses from among the public IP addresses available for Internet communications. This presents a problem due to the large number of data acquisition sites, and even larger number of hosts, since each data acquisition site typically has its own local area network to which numerous hosts are connected. Purchasing and maintaining public IP addresses for all these hosts may be very expensive.
Task priorities and scarcity of public IP addresses may lead to another problem. In the context of well logging, data acquisition is usually a much higher priority than connecting to the WAN and centralized information handling resources. That is, data acquisition sites for well logging are commonly mobile units that connect and disconnect from the network as they travel from one well location to another. Establishing a link to the WAN at a remote location takes time, whereas there may be a pressing need for data acquisition to commence immediately upon a mobile data acquisition unit arriving at the location. So the service provider's technician may immediately set up one or more data acquisition hosts on a local area network (“LAN”) in the mobile unit, with attendant IP address, subnet mask and gateway assignments. Then, once the service provider's technician has begun data logging, he or she may turn to establishing a WAN link, such as by setting up a satellite dish.
Moreover, to conserve the number of public IP addresses used by the service provider, it is common that non-public IP addresses are assigned to one or more of the hosts on the LAN. Thus, once the WAN equipment is in place, the IP address for one of the hosts may have to be changed to one of the public IP addresses so that the host can communicate on the WAN. When the host is performing well logging by communicating with down-hole data transmitters on the LAN, changing the host's IP address temporarily disrupts communication between the host and the transmitters. Obviously it is disadvantageous to interrupt well logging in order to initiate communication on the WAN.
Another problem that must be dealt with for this system concerns security. That is, an extensive private WAN such as this greatly improves communication between the data acquisition sites and other information handling resources, but it also gives rise to security issues. In this context security is particularly important, since the data collected for a client at a remote location ordinarily has great commercial value. Security difficulties are aggravated in the particular circumstances of the present invention because of the mobile units connecting and disconnecting from the network.
From this background it should be appreciated that there are a number of problems which need to be addressed to manage connection of data acquisition sites to a network.